Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.
Horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases.
The temperature is constant during a phase change (melting or boiling), so the graph is a horizontal line.
The temperature increases when a single phase (solid, liquid, or gas) is heated, so the graph for these changes has an upward slope.
A is wrong. A horizontal line shows a constant temperature.
B is wrong. There are no vertical lines in a heating curve.
D is wrong. A horizontal line does correspond to an increase in temperature.
See attached image for the right answer.
metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.
for example, electronic configuration of sodium is and electronic configuration of phosphorous is .
when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.
the reaction will be as follows.
there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.
thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.